流域水生态安全评估方法

Research on Evaluation Methods for Riverine Aquatic Ecological Security

为建立合理的流域水生态安全评估指标体系,以流域为对象,对水生态安全内涵进行了阐释,并对流域水生态安全评估指标进行了系统分析.基于"压力、状态、功能、风险"四要素,构建了"目标层-方案层-要素层-指标层"的评估体系,其中方案层包括水生态压力、水生态状况、水生态功能和水生态风险4个方面,涵盖土地利用、水资源利用、污染物排放、栖息地状态、水生态质量、水产品供给、休闲娱乐、水环境净化、重金属风险等9个评估要素18个评估指标,并详尽表述了各评估指标的内涵及其计算方法.采用综合指数法计算ESI(生态安全指数),并根据ESI得分将水生态系统的安全评级分为安全(3.5≤ESI≤4.0)、较安全(2.5≤ESI<3.5)、一般(1.5≤ESI<2.5)、不安全(0.5≤ESI<1.5)和很不安全(0≤ESI<0.5)5个级别,构建了多指标的流域水生态安全评估方法.

To establish useful evaluation methods for riverine aquatic ecological security,the connotations of aquatic ecological security were clarified. Based on four factors（ i. e.,pressure,state,function and risk）,an evaluation framework was composed of aim,project,element and index aspects. The project aspect in the evaluation index system was firstly established from the four factors,and covered nine elements,including land use,water resources utilization,pollutant discharge,habitat status,aquatic ecology quality,aquatic product supply,entertainment,purification of aquatic environment and heavy metal contamination,and eighteen indexes. Therein,the definition,calculation,assignment and assessment grading for each index were also described. By ecological security index（ ESI）,aquatic ecological assessment grading was divided into five grades,including safe（ 3. 5≤ESI≤4. 0）,relatively safe（ 2. 5≤ESI 3. 5）,fair（ 1. 5≤ESI 2. 5）,unsafe（ 0. 5≤ESI 1. 5） and completely unsafe（ 0≤ESI 0. 5）. Thus,the sub-basin-scale ecological security evaluation system with multiple indexes was formulated accordingly.